Towards automated verification of smart contract fairness

Abstract

Smart contracts are computer programs allowing users to define and execute transactions automatically on top of the blockchain platform. Many of such smart contracts can be viewed as games. A game-like contract accepts inputs from multiple participants, and upon ending, automatically derives an outcome while distributing assets according to some predefined rules. Without clear understanding of the game rules, participants may suffer from fraudulent advertisements and financial losses. In this paper, we present a framework to perform (semi-)automated verification of smart contract fairness, whose results can be used to refute false claims with concrete examples or certify contract implementations with respect to desired fairness properties. We implement FairCon, which is able to check fairness properties including truthfulness, efficiency, optimality, and collusion-freeness for Ethereum smart contracts. We evaluate FairCon on a set of real-world benchmarks and the experiment result indicates that FairCon is effective in detecting property violations and able to prove fairness for common types of contracts. CCS CONCEPTS • Software and its engineering → Software verification; Software verification and validation.

sFuzz2.0: Storage‐access pattern guided smart contract fuzzing

“…Ethor 40 proposes a static Smart Contract analyzer based on an abstraction of bytecode semantics based on Horn clauses. FairCon 41 is designed to verify smart contract fairness. Clairvoyance 12 is a cross‐contract and cross‐function static analyzer focused on reentrancy bugs.…”

A Survey of Smart Contract Formal Specification and Verification

“…While its precise definition is subjective in the presence of several competing users [114], game-theoretical techniques [52,124] analyze utility functions of participants as a reflection of contract fairness. The theory of mechanism design has also been applied in the verification of fairness properties of game contracts [132].…”

“…Another auction specification [36] states that the items belong to the auctioneer as long as the auction is open and to the highest bidder after the auction is closed. Invariants for an auction contract in [132] require that the bidder with the highest bid becomes the winner and the highest bid becomes the clear price.…”

“…The study of smart contract fairness is complicated by the multi-user environment of its execution model and unknown intentions of contract designers. Still, to analyze such high-level properties, including fairness, researchers currently apply techniques from the domains of game theory and mechanism design [52,124,132].…”

Securing smart contracts with formal verification and automated program repair

“…Even though an accurate definition of fairness is subjective (especially in the presence of several competing parties [160]), some techniques utilize game-theoretical concepts [66,174] to define and analyze utility functions of participants as an approximation of smart contract fairness. Techniques from the field of mechanism design have also been used to verify fairness of auction and voting smart contracts [193].…”